Larynx

Larynx

It is important to appreciate that the main function of the larynx is not the production of voice but the protection of the tracheobronchial airway and lungs. In order to achieve this, the larynx, together with the base of the tongue, forms the protec tive sphincter that closes o ff the airway during swallowing. It is only an evolutionary by-product that, in humans and some other mammals, the larynx is responsible for the production of sound. The larynx comprises a cartilaginous framework (tha ossify in later life), which consists of the hyoid bone above, the thyroid and cricoid cartilages and the intricate arytenoid cartilages posteriorly . The cricoid cartilage is the only complete ring in the entire airwa y and bounds the subglottis, which is the narrowest point of the airway in children. This is the most common site for damage from an endotrac heal tube used for intensive care unit ventilation in seriously ill patients. A purely anatomical description of the larynx divides it into the supraglottis, glottis and subglottis ( Figure 52.6 ). The true - - t may

Nasal cavity Hard palate Nasopharynx Soft palate Oropharynx Tongue Epiglottis Laryngopharynx Vocal cords Oesophagus Trachea Epiglottis Hyoid Thyrohyoid ligament Thyroid Arytenoid cartilage cartilage Cricothyroid Cricoid ligament cartilage Cricoid cartilage Trachea Epiglottis Hyoid Supraglottis S upr Pre-epiglottic space Ventricular fold Glottis (false cor d) Laryngeal ventricle Subglottis Vocal fold (true cord) Cricothyr oid space Tracheal cartilage Figure 52.6 Anatomy of the larynx.

vocal folds (often incorrectly called the vocal cords) are nor mally white, in contrast to the pink mucosa of the rest of the larynx and airway . The true vocal folds meet anteriorly at the midlevel of the thyroid cartilage, whereas posteriorly the separate and attached to an arytenoid cartilage. This arrange ment produces the ‘V’ shape of the glottis ( Figure 52.7

Posterior pharyngeal wall Trachea Arytenoid cartilage Aryepiglottic fold Vocal fold Epiglottis Base of tongue (b) Figure 52.7 (a) Flexible nasendoscopy view of the larynx with the vocal folds abducted. (b) Flexible nasendoscopy view of the larynx with the vocal folds adducted.

Larynx

It is important to appreciate that the main function of the larynx is not the production of voice but the protection of the tracheobronchial airway and lungs. In order to achieve this, the larynx, together with the base of the tongue, forms the protec tive sphincter that closes o ff the airway during swallowing. It is only an evolutionary by-product that, in humans and some other mammals, the larynx is responsible for the production of sound. The larynx comprises a cartilaginous framework (tha ossify in later life), which consists of the hyoid bone above, the thyroid and cricoid cartilages and the intricate arytenoid cartilages posteriorly . The cricoid cartilage is the only complete ring in the entire airwa y and bounds the subglottis, which is the narrowest point of the airway in children. This is the most common site for damage from an endotrac heal tube used for intensive care unit ventilation in seriously ill patients. A purely anatomical description of the larynx divides it into the supraglottis, glottis and subglottis ( Figure 52.6 ). The true - - t may

Nasal cavity Hard palate Nasopharynx Soft palate Oropharynx Tongue Epiglottis Laryngopharynx Vocal cords Oesophagus Trachea Epiglottis Hyoid Thyrohyoid ligament Thyroid Arytenoid cartilage cartilage Cricothyroid Cricoid ligament cartilage Cricoid cartilage Trachea Epiglottis Hyoid Supraglottis S upr Pre-epiglottic space Ventricular fold Glottis (false cor d) Laryngeal ventricle Subglottis Vocal fold (true cord) Cricothyr oid space Tracheal cartilage Figure 52.6 Anatomy of the larynx.

vocal folds (often incorrectly called the vocal cords) are nor mally white, in contrast to the pink mucosa of the rest of the larynx and airway . The true vocal folds meet anteriorly at the midlevel of the thyroid cartilage, whereas posteriorly the separate and attached to an arytenoid cartilage. This arrange ment produces the ‘V’ shape of the glottis ( Figure 52.7

Posterior pharyngeal wall Trachea Arytenoid cartilage Aryepiglottic fold Vocal fold Epiglottis Base of tongue (b) Figure 52.7 (a) Flexible nasendoscopy view of the larynx with the vocal folds abducted. (b) Flexible nasendoscopy view of the larynx with the vocal folds adducted.